Orangutans modify their gestural signaling according to their audience's comprehension (original) (raw)

Orangutans’ Comprehension of Zoo Keepers’ Communicative Signals

Animals

Zoological institutions often encourage cooperative interactions between keepers and animals so as to promote animals’ welfare. One useful technique has been conditioning training, whereby animals learn to respond to keepers’ requests, which facilitates a number of, otherwise sensitive, daily routines. As various media have been used to convey keepers’ instructions, the question remains of which modality is best to promote mutual understanding. Here, we explored this question with two captive female orangutans. In the first experiment, we compared orangutans’ understanding of previously acquired instructions when those were performed with verbal signals only, gazes only, gestures only, and when all those modalities were combined. Our results showed that gestures were sufficient for successful comprehension by these two apes. In the second experiment, we asked whether this preference could be driven by the non-arbitrary relationship that gestures bear to what they refer to, through i...

Gestural communication of orangutans ( Pongo pygmaeus )

Gesture, 2006

This study represents a systematic investigation of the communicative repertoire of Sumatran orangutans (Pongo pygmaeus abelii), with a focus on intentional signals in two groups of captive orangutans. The goal was to analyze the signal repertoire with respect to (1) the number and frequency of signals (gestures, facial expressions, and actions), (2) the variability of individual repertoires as a function of group, age class, and sex, and (3) the flexibility of use in terms of 'means-end dissociation' and 'audience effects' and to interpret the findings in terms of the ecology, social structure and socio-cognitive skills of orangutans. The results show that orangutans use a remarkable number of signals including tactile and visual gestures as well as several more complex actions, though few facial expressions and no auditory gestures were observed. One third of signals were used within a play context, followed by one fourth of interactions in the context of ingestion. Although the repertoire included several visual gestures, most of the signals produced were tactile gestures and they were used particularly in the contexts of affiliation and agonism, whereas visual gestures dominated in the context of grooming, ingestion and sexual behavior. Individual repertoires showed a remarkable degree of variability as a function of age and group affiliation. Orangutans used their signals flexibly in several functional contexts and adjusted the signal they used depending on the attentional state of the recipient, similar to findings of other great ape species and gibbons. Thus, the communicative behavior of orangutans is characterized by a variable and flexible use of signals possibly reflecting their highly variable social structure and their sophisticated socio-cognitive skills, with the dominance of tactile gestures corresponding to the arboreal nature of this species.

Gestural communication of orangutans (Pongo pygmaeus)

Gesture, 2006

Semantics of primate gestures: intentional meanings of orangutan gestures

Animal Cognition, 2010

Great ape gesture has become a research topic of intense interest, because its intentionality and flexibility suggest strong parallels to human communication. Yet the fundamental question of whether an animal species’ gestures carry specific meanings has hardly been addressed. We set out a systematic approach to studying intentional meaning in the gestural communication of non-humans and apply it to a sample of orangutan gestures. We propose that analysis of meaning should be limited to gestures for which (1) there is strong evidence for intentional production and (2) the recipient’s final reaction matches the presumed goal of the signaller, as determined independently. This produces a set of “successful” instances of gesture use, which we describe as having goal–outcome matches. In this study, 28 orangutans in three European zoos were observed for 9 months. We distinguished 64 gestures on structural grounds, 40 of which had frequent goal–outcome matches and could therefore be analysed for meaning. These 40 gestures were used predictably to achieve one of 6 social goals: to initiate an affiliative interaction (contact, grooming, or play), request objects, share objects, instigate co-locomotion, cause the partner to move back, or stop an action. Twenty-nine of these gestures were used consistently with a single meaning. We tested our analysis of gesture meaning by examining what gesturers did when the response to their gesture did not match the gesture’s meaning. Subsequent actions of the gesturer were consistent with our assignments of meaning to gestures. We suggest that, despite their contextual flexibility, orangutan gestures are made with the expectation of specific behavioural responses and thus have intentional meanings as well as functional consequences.

Communicative intentions in wild chimpanzees: Persistence and elaboration in gestural signalling

We examine evidence for communicative intent during conspecific interactions in wild chimpanzees (Budongo Forest, Uganda), focusing on persistence in gestural communication. Previous research indicates that great apes have large gestural repertoires and produce gestural communication in a flexible and intentional manner, including the production of gesture sequences. Although there is a lack of consensus on the form and function of sequences, there is some evidence that sequences are produced when signallers fail to receive any response from a recipient. Here we provide first systematic evidence for communicative persistence in wild chimpanzees. Rather than examining only the presence or absence of a response, we used the most commonly observed response to assign meanings to gestures and examined sequence production in relation to response congruency. Chimpanzees ceased communication if successful, but persevered when unsuccessful. Chimpanzees repeated gestures when a response partially matched their goal but substituted the original gesture when a response was incongruent. Persistence was also mediated by recipient intent to respond, with more sequences produced within competitive than affiliative contexts. Gestures within sequences were homogenous in semantic meaning and signallers continued until the response matched the assigned meaning of the initial gesture. Gestural sequence production was not primarily affective; gesture intensity (in terms of modality) did not increase within sequences. Chimpanzee gestural sequences emerged to achieve specific outcomes; given variability in recipient behaviour following initial gestures, signallers were flexible in their persistence towards these goals.

Orangutan Pantomime: Elaborating the Message

Biology Letters, 2010

We present an exploratory study of forest-living orangutan pantomiming, i.e. gesturing in which they act out their meaning, focusing on its occurrence, communicative functions, and complexities. Studies show that captive great apes may elaborate messages if communication fails, and isolated reports suggest that great apes occasionally pantomime. We predicted forest-living orangutans would pantomime spontaneously to communicate, especially to elaborate after communication failures. Mining existing databases on free-ranging rehabilitant orangutans’ behaviour identified 18 salient pantomimes. These pantomimes most often functioned as elaborations of failed requests, but also as deceptions and declaratives. Complexities identified include multimodality, re-enactments of past events and several features of language (productivity, compositionality, systematicity). These findings confirm that free- ranging rehabilitant orangutans pantomime and use pantomime to elaborate on their messages. Further, they use pantomime for multiple functions and create complex pantomimes that can express propositionally structured content. Thus, orangutan pantomime serves as a medium for communication, not a particular function. Mining cases of complex great ape communication originally reported in functional terms may then yield more evidence of pantomime.

Intentional communication between wild bonnet macaques and humans

Scientific Reports

Comparative studies of nonhuman communication systems could provide insights into the origins and evolution of a distinct dimension of human language: intentionality. Recent studies have provided evidence for intentional communication in different species but generally in captive settings. We report here a novel behaviour of food requesting from humans displayed by wild bonnet macaques Macaca radiata, an Old World cercopithecine primate, in the Bandipur National Park of southern India. Using both natural observations and field experiments, we examined four different behavioural componentscoo-calls, hand-extension gesture, orientation, and monitoring behaviour-of food requesting for their conformity with the established criteria of intentional communication. Our results suggest that food requesting by bonnet macaques is potentially an intentionally produced behavioural strategy as all the food requesting behaviours except coo-calls qualify the criteria for intentionality. We comment on plausible hypotheses for the origin and spread of this novel behavioural strategy in the study macaque population and speculate that the cognitive precursors for language production may be manifest in the usage of combination of signals of different modalities in communication, which could have emerged in simians earlier than in the anthropoid apes. Organised human language is perhaps one of the most important behaviours that distinguish human beings from all other species 1,2 , with intentionality lying at the core of this communication system 3-6. The biological origin and evolution of this crucial dimension of human language, however, remains underexplored but could benefit from comparative studies of the communication systems of our closest living relatives, nonhuman primates (henceforth, primates). Intentional communication in humans requires an understanding of the mental states of articulators, which, in turn, requires complex cognitive capacities 7,8. Subsequently, intentionality in animal communication systems was operationalised through different orders of 'intentionality' 9-11. Zero-order intentionality, for example, is merely reflexive communication, not involving any sophisticated cognitive processes. This then proceeds to higher orders of intentionality, which involves some recognition of one's own mental states as well as those of audience, culminating in the capacity of the actor to successfully communicate its own intentions and goals to the audience, the characteristic feature of higher-order intentionality 10-13. Although this approach is practically helpful to identify intentionality in human communication, recent studies have suggested that mental-state attribution may not be a necessary criterion to typify intentional communication, particularly in non-humans 13. This has given rise to various general behavioural criteria to qualify a communicative signal to be intentional. These criteria include (1) the social use of the communicative act, as indicated by the signal being directed to particular recipients, modified by various factors, such as the presence or composition of the attendant audience; (2) sensitivity of the signaller to the attentional states of the recipients; (3) manipulation of the attentional states of recipients to attract attention, particularly when a mutual attention state between the signaller and recipient is absent or the signaller moves itself into the line of view of a recipient; (4) monitoring the responses of the audience and (5) persistence in the production and/or elaboration of the signal until the desired communicative goal is met 4,14,15 (but see ref. 13 for a recently proposed, simpler framework for intentional communication in animals).

Orangutans modify their gestural signaling according to their audience's comprehension (original) (raw)

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